Apparatus for machining a concial ring

ABSTRACT

An apparatus is described for machining a conical ring, particularly a friction ring, which has inside and outside conical machinable surfaces having parallel radially aligned generatrices, which apparatus comprises two coaxial machining tools which consist of an outer tool having an inside conical machining surface for machining the outside machinable surface of said ring and an inner tool having an outside conical machining surface for machining said inside machinable surface of said ring, which machining tools are mounted to be rotatable about a common axis relative to said ring and said ring is adapted to be held between said tools so as to be centered on said axis. The tools are mounted to be axially movable relative to each other to a range of positions in which said outside concial machinable surface of said ring is adapted to be in sliding contact with said inside conical machining surface of said outer tool and said outside conical machinable surface is adapted to be in sliding contact with said inside conical machining surface of said outer tool and said outside conical machinable surface is adapted to be in sliding contact with said inside conical machining surface of said outer tool at the same time and said tools are axially movable toward each other to a predetermined position, which is defined by stop means.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an apparatus for machining a conical ring,particularly a friction ring, which has inside and ouside conicalmachinable surfaces having parallel radially aligned generatrices, whichapparatus comprises two coaxial machining tools which consist of anouter tool having an inside conical machining surface for machining theoutside machinable surface of said ring and an inner tool having anoutside conical machining surface for machining said inside machinablesurface of said ring, which machining tools are mounted to be rotatableabout a common axis relative to said ring and said ring is adapted to beheld between said tools so as to be centered on said axis.

2. Description of the Prior Art

To machine the conical friction surfaces of friction ring having afriction lining at least on one of its outside and inside surfaces foruse in clutches or brakes, for example, it is known to provide toolswhich have an outside conical surface that is provided with adiamond-containing coating for polishing the inside friction surface ofthe conical friction ring. Because the friction ring must be held inposition relative to the rotating tool which extends into the opening ofthe ring, the accuracy of the machining will depend on the centering ofthe tool relative to the conical ring and on the elastic deformationwhich is imparted to the ring by the tool. That elastic deformation ofthe ring adversely affects the accuracy which can be ensured. Similarremarks are applicable to the machining of the outside friction surfacesof a conical friction ring with a tool which comprises an inside conicalmachining surface for machining the outside friction surface of thering. Because in a conical friction ring having inside and outsidefriction linings the tolerances specified for the machining of eachfriction surface accumulate to a total tolerance, such surfaces cannotbe machined to a very high accuracy. Besides, the tool must be fixed indifferent positions and this involves additional work.

SUMMARY OF THE INVENTION

For this reason it is an object of the invention to provide for themachining of a conical ring, particularly a friction ring, which hasinside and outside conical machinable surfaces having parallel radiallyaligned generatrices, an apparatus which is designed to permit anaccurate machining of the inside and outside conical machinable surfaceswith small deviations and with a relatively low expenditure of work.

In an apparatus of the kind described first hereinbefore that object isaccomplished in accordance with the invention in that the two tools areadapted to be driven to rotate relative to each other and are coaxiallyarranged so that said inside and outside conical machining surfacesdefine between the a conical gap, which is adapted to accommodate theconical ring in a position in which it is adapted to float relative tosaid tools, and said tools are mounted to be axially movable relative toeach other to a predetermined relative position.

A fast machining of the conical ring is ensured because the outside andinside conical friction surfaces of the conical friction ring aremachined at the same time between the opposite inside conical machiningsurface and the outside conical machining surface formed on respectiverotating tools, between which the ring is floating. As a result,separate means for fixing the workpiece are not needed, the structuralexpenditure is reduced and the ring can be more accurately machinedbecause the conical ring can freely move into contact with the machiningsurfaces of the tools. This will prevent an occurrence of defects whichcould be caused by a misalignment of workpieces relative to the tool.Because the two conical machinable surfaces are machined at the sametime by the two tools, between which the ring is floating, the ring willbe machined under conditions which are similar to its conditions of useso that particularly small tolerances can be specified with a view tothe intended use of the ring. Besides, the fact that the tools areaxially moved toward each other to a predetermined position permits theinside and outside diameters of the workpiece to be specified with asmall tolerance. The tools may consist of grinding tools ordiamond-carrying polishing tools, which may be selected in dependence onthe material of which the machinable surfaces are made.

The predetermined position to which said two tools are axially movablerelative to each other may be defined by stop means, which may beaxially adjustable in adaptation to different conical rings to bemachined.

For a simultaneous machining of the inside and outside machinablesurfaces of a conical ring, the two tools must be rotated relative toeach other. Particularly desirable conditions will be obtained if thetwo tools are driven to rotate in mutually opposite senses.

There is a risk that a conical ring to be machined may not uniformlycontact the tools throughout the periphery of the ring. That risk can beavoided in accordance with the invention in that the conical ring isaxially engaged at opposite ends by two stops, which are axially guidedto ensure that the workpiece can float relative to the ring during anaxial movement of the two tools toward each other. Because the stops areaxially displaceable it is ensured that the outside and inside surfacesof the conical ring will not be machined until a simultaneous machiningof the ring on both sides is ensured because the ring is engaged by saidtools on both sides.

A simple design will be obtained if the stops for axially engaging theconical ring are axially supported by springs on the holders for the twotools. In that case an axial adjustment of the two tools relative toeach other after a ring to be machined has been inserted between the twotools will have the result that the ring is initally axially retainedbetween the stops before the tools contact the machinable surfaces ofthe ring. Because the stops are resiliently supported in an axialdirection the ring is axially displaceable relative to the two tools asis required.

The machining forces exerted on the ring should be uniformly distributedto the two tools. This requires the ring to be freely rotatable betweenthe two tools. If the workpiece is held against a canting betweenaxially spaced apart stops, that requirement can be met in a simplemanner in that the axially spaced apart stops are mounted for a rotationabout the tool axis relative to the toolholding means.

BRIEF DESCRIPTION OF THE DRAWING

The drawing is a simplified axial sectional view showing an illustrativeembodiment of an apparatus in accordance with the invention formachining a conical friction ring having inside and outside conicalfriction surfaces.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The illustrated apparatus for machining a conical friction ring 1 havingan inside conical friction surface 2 and an outside conical frictionsurface 3 comprises two tools, namely, an outer tool 4 having an insideconical machining surface 5 for machining the outside friction surface 3and an inner tool 6 having an outside conical machining surface 7 formachining the inside friction surface 2 of the conical friction ring 1.Said tools 4 and 5 are coaxially rotatably mounted and are adapted to bedriven to rotate in mutually opposite senses by drive means which arenot shown for the sake of clearness.

To permit an axial displacement of the two tools 4 and 5 relative toeach other, the tool 4 having the inside conical machining surface 5 isaxially fixedly held in the illustrated embodiment and the other tool 6is rotatably mounted in an axially displaceable toolholder 8. As aresult, a friction ring 1 can be inserted into the cavity defined by theinside conical machining surface 5 of the tool 4 and the tool 6 can beengaged by the outside conical machining surface 7 of the friction ring1 and can then be machined by both tools at the same time. For thatpurpose the tools may preferably consist of diamond-carrying polishingtools or of grinding tools.

A holder 9 comprising an annular stop 10 for axially engaging thefriction ring 1 is disposed within the annular tool 4 provided with theinside conical machining surface 5. The holder 9 is mounted to beaxially guided relative to the tool 4 and is axially supported by meansof compression springs 11 on an axial rolling element bearing 12. Thatresilient support permits an axial displacement of the annular stop 10relative to the toolholder for the tool 4. Similarly, an annular stop 13for the friction ring 1 is associated with the tool 6 which has theoutside conical machining surface 7. The stop 13 is constituted by aholder 14, which is supported by springs 15 on the toolholder 8, and theholder 14 is slidably guided relative to the toolholder 8. The holder 14is rotatably supported relative to the tool 6 by means of an axialrolling element bearing 16.

When a friction ring 1 to be machined is inserted into the cavitydefined by the inside conical machining surface 5 of the tool 4, thatfriction ring 1 will initially axially engage the stop 10. Thereafterthe tool 6 provided with the outside conical machining surface 7 isaxially moved by the associated toolholder 8 into engagement with thefriction ring 1, which is now contacted at its machinable surfaces 2 and3 by the respective tools 4 and 6. At this time the friction ring 1 isaxially engaged at opposite ends by the stops 10 and 13 to prevent acanting of the ring. Because said stops are resiliently supported, thering will still be axially displaceable while it is held againstcanting. For this reason the friction ring 1 can be machined on itsmachinable surfaces 2 and 3 by the inside conical machining surface 5 ofthe outer tool 4 and the outside conical machining surface 7 of theinner tool 6 at the same time. On the left side of the drawing theapparatus is shown in the position assumed shortly before the frictionring 1 is axially engaged at opposite ends by both stops 10 and 13. Onthe right side of the drawing the position is shown which is assumedwhen the workpiece has been machined and in which the outside conicalmachining surface 7 of the tool 6 has been moved into the cavity that isdefined by the inside conical machining surface 5 of the tool 4 to adepth which is defined by stops 10 and 13. The friction ring 1 isaxially held between the stops 10 and 13 so that it cannot be canted butis still axially displaceable relative to the tools.

In the illustrated embodiment the friction ring 1 is provided withaxially protruding coupling elements 17, which are distributed aroundits periphery and which are engageable by the stop 13 which isassociated with the tool 6.

It will be understood that the invention is not restricted by theillustrated embodiment. For instance, the apparatus may be used tomachine not only friction rings but any conical ring which has insideand outside conical machinable surfaces having parallel radially alignedgeneratrices. Besides, the design features of the illustrativeillustrated apparatus may be replaced by different design featuresbecause it is merely essential that the conical ring 1 which is to bemachined can float between an inner conical machining surface and anouter conical machining surface of respective tools, which rotaterelative to each other, and the tools are axially moved relative to eachother so that the two machinable surfaces are machined at the same time.

I claim:
 1. An apparatus for machining a conical ring having inside andoutside conical machinable surfaces defining parallel generatrices,which comprises(a) an outer tool, and (b) an inner tool,(1) the toolsbeing mounted coaxially to be rotatable about a common axis, (2) theouter tool having an inside conical machining surface for machining theoutside conical machinable surface of the ring and the inner tool havingan outside conical machining surface for machining the inside conicalmachinable surface of the ring when the ring is disposed between themachining surfaces of the tools and is centered on the common axis, and(3) the tools being mounted to be axially movable relative to each otheralong the common axis to a range of positions wherein the machinablesurfaces of the ring are in sliding contact with the machining surfacesof the tools and into a predetermined position relative to each other.2. The apparatus set forth in claim 1, further comprising stop means forlimiting the axial movement of said tools toward each other in saidpredetermined position.
 3. The apparatus set forth in claim 2, whereinsaid stop means are adjustable along said common axis.
 4. The apparatusset forth in claim 1 wherein the tools are mounted for rotating inopposite senses about said common axis.
 5. An apparatus for machining aconical ring having inside and outside conical machinable surfacesdefining parallel generatrices, which comprises(a) an outer tool, (b) aninner tool,(1) the tools being mounted coaxially to be rotatable about acommon axis, (2) the outer tool having an inside conical machiningsurface for machining the outside conical machinable surface of the ringand the inner tool having an outside conical machining surface formachining the inside conical machinable surface of the ring when thering is disposed between the machining surfaces of the tools and iscentered on the common axis, and (3) the tools being mounted to beaxially movable relative to each other along the common axis to a rangeof positions wherein the machinable surfaces of the ring are in slidingcontact with the machining surfaces of the tools and into apredetermined position relative to each other, and (c) two stops spacedapart along the common axis and defining the predetermined position, thestops being(1) engageable by the ring at opposite ends thereof when themachinable surfaces of the ring are disposed between the machiningsurfaces of the tools, and (2) each stop being mounted to be axiallyguided relative to the tools.
 6. The apparatus set forth in claim 5,whereintwo toolholding means are provided, which are spaced apart alongsaid common axis, each of said tools is rotatably mounted in one of saidtoolholding means, and each of said stops is axially supported by springmeans against one of said toolholding means.
 7. The apparatus set forthin claim 5, wherein at least one of said stops is mounted to berotatable about said common axis relative to said toolholding means. 8.The apparatus set forth in claim 5, wherein at least one of said stopsis mounted to be rotatable about said common axis relative to saidtools.
 9. The apparatus set forth in claim 5, whereinone of said stopsis mounted to be rotatable about said common axis relative to saidtoolholding means and the other of said stops is mounted to be rotatableabout said common axis relative to said tools.